Here's my step-by-step explanation:
We're just gonna factor.
If your teacher has spoken of FOIL, then he/she has probably said that it means First Outer Inner Last and that it helps with distributing problems like these.
Right, so let's get to it.

Can you see the FOIL method being spread out here? Let's keep going.

Hope this helps, and let me know if I made a mistake! ^_^
Answer:
+ C
This is my first time doing a double integral, so im only 90% sure in my answer
Step-by-step explanation:
You pretty much want to take the double integral of sinx + cosx
The anti-derivative of sinx = -cosx
The anti-derivative of cosx = sinx
So f' = -cosx + sinx
Now lets take the integral of f':
The anti-derivative of -cosx = sinx
The anti-derivative of sinx = -cosx
So, f(x) = sinx - cosx
Answer:

Step-by-step explanation:
Difference between tourists visiting France and Italy =
×
× 

Difference between population of tourists in France and Italy are
people.
Answer: 85 student tickets, 65 adult tickets.
Let's say the # of students is x and the # of adults is y. The two equations we get are 7.50x + 15y = 1612.50 and x + y = 150
x = 150 - y
7.5(150-y) + 15y = 1612.5
1125-7.5y+15y=1612.5
7.5y=487.5
y=65
x=150-65
x=85
Hope this helps!